Investigation of how the presence of a female germline and the receipt of sperm during mating influences gene expression changes in adult female head tissues after mating. Nicole R Newell¹, Justin E Dalton¹, Peter L Chang², Sergey V Nuzhdin², Michelle N Arbeitman¹. 1) Biomedical Science, Florida State University, Tallahassee, FL; 2) Molecular & Computational Biology, University of Southern California, Los Angeles, CA.

   Drosophila melanogaster females, once mated, undergo both physiological and behavioral changes that last about a week. This post-mating response includes increased immunity and egg laying, changes in metabolic activity, and decreased receptivity to courtship. These changes are initiated by the receipt of the male accessory gland proteins (Acps) and sperm. One Acp, Sex Peptide (SP) immediately circulates systemically eliciting a short-term post-mating response, whereas another portion is bound to the sperm tail and is gradually released by cleavage. It is this gradual release of SP from sperm that maintains the long-term post-mating response. We have previously shown that different sets of genes are significantly differentially expressed in female head tissues at four different time points we assayed post-mating, as compared to age-matched virgin females. However, what is still unknown is the contribution of the presence of a germline, egg production and egg laying in females on these gene expression changes. Furthermore, the effect of receipt of sperm on gene expression changes in female adult head tissues is not understood. This is especially interesting considering the long-term effect on female behavior from the gradual release of SP from sperm. Illumina RNA-seq libraries were made from mRNA derived from adult heads of: (1) wild type females that had been mated to males with or without a germline, (2) females with or without a germline that had been mated to wild type males, and (3) virgin females of the same genotypes. We examined gene expression one and three days post-mating, to see the early and the sustained gene expression responses to mating. The analysis of the Illumina RNA-Seq data we obtained on gene and transcript-isoform expression will be presented.